drivers/spi/altera_spi.c

   1 /*
   2  * Altera SPI driver
   3  *
   4  * based on bfin_spi.c
   5  * Copyright (c) 2005-2008 Analog Devices Inc.
   6  * Copyright (C) 2010 Thomas Chou <thomas@wytron.com.tw>
   7  *
   8  * SPDX-License-Identifier:     GPL-2.0+
   9  */
  10 #include <common.h>
  11 #include <dm.h>
  12 #include <errno.h>
  13 #include <malloc.h>
  14 #include <spi.h>
  15 #include <fdtdec.h>
  16 #include <asm/io.h>
  17
  18 DECLARE_GLOBAL_DATA_PTR;
  19
  20 #ifndef CONFIG_ALTERA_SPI_IDLE_VAL
  21 #define CONFIG_ALTERA_SPI_IDLE_VAL 0xff
  22 #endif
  23
  24 struct altera_spi_regs {
  25         u32     rxdata;
  26         u32     txdata;
  27         u32     status;
  28         u32     control;
  29         u32     _reserved;
  30         u32     slave_sel;
  31 };
  32
  33 struct altera_spi_platdata {
  34         struct altera_spi_regs *regs;
  35 };
  36
  37 struct altera_spi_priv {
  38         struct altera_spi_regs *regs;
  39 };
  40
  41 #define ALTERA_SPI_STATUS_RRDY_MSK      BIT(7)
  42 #define ALTERA_SPI_CONTROL_SSO_MSK      BIT(10)
  43
  44 static void spi_cs_activate(struct udevice *dev, uint cs)
  45 {
  46         struct udevice *bus = dev->parent;
  47         struct altera_spi_priv *priv = dev_get_priv(bus);
  48         struct altera_spi_regs *const regs = priv->regs;
  49
  50         writel(1 << cs, &regs->slave_sel);
  51         writel(ALTERA_SPI_CONTROL_SSO_MSK, &regs->control);
  52 }
  53
  54 static void spi_cs_deactivate(struct udevice *dev)
  55 {
  56         struct udevice *bus = dev->parent;
  57         struct altera_spi_priv *priv = dev_get_priv(bus);
  58         struct altera_spi_regs *const regs = priv->regs;
  59
  60         writel(0, &regs->control);
  61         writel(0, &regs->slave_sel);
  62 }
  63
  64 static int altera_spi_claim_bus(struct udevice *dev)
  65 {
  66         struct udevice *bus = dev->parent;
  67         struct altera_spi_priv *priv = dev_get_priv(bus);
  68         struct altera_spi_regs *const regs = priv->regs;
  69
  70         writel(0, &regs->control);
  71         writel(0, &regs->slave_sel);
  72
  73         return 0;
  74 }
  75
  76 static int altera_spi_release_bus(struct udevice *dev)
  77 {
  78         struct udevice *bus = dev->parent;
  79         struct altera_spi_priv *priv = dev_get_priv(bus);
  80         struct altera_spi_regs *const regs = priv->regs;
  81
  82         writel(0, &regs->slave_sel);
  83
  84         return 0;
  85 }
  86
  87 static int altera_spi_xfer(struct udevice *dev, unsigned int bitlen,
  88                             const void *dout, void *din, unsigned long flags)
  89 {
  90         struct udevice *bus = dev->parent;
  91         struct altera_spi_priv *priv = dev_get_priv(bus);
  92         struct altera_spi_regs *const regs = priv->regs;
  93         struct dm_spi_slave_platdata *slave_plat = dev_get_parent_platdata(dev);
  94
  95         /* assume spi core configured to do 8 bit transfers */
  96         unsigned int bytes = bitlen / 8;
  97         const unsigned char *txp = dout;
  98         unsigned char *rxp = din;
  99         uint32_t reg, data, start;
 100
 101         debug("%s: bus:%i cs:%i bitlen:%i bytes:%i flags:%lx\n", __func__,
 102               bus->seq, slave_plat->cs, bitlen, bytes, flags);
 103
 104         if (bitlen == 0)
 105                 goto done;
 106
 107         if (bitlen % 8) {
 108                 flags |= SPI_XFER_END;
 109                 goto done;
 110         }
 111
 112         /* empty read buffer */
 113         if (readl(&regs->status) & ALTERA_SPI_STATUS_RRDY_MSK)
 114                 readl(&regs->rxdata);
 115
 116         if (flags & SPI_XFER_BEGIN)
 117                 spi_cs_activate(dev, slave_plat->cs);
 118
 119         while (bytes--) {
 120                 if (txp)
 121                         data = *txp++;
 122                 else
 123                         data = CONFIG_ALTERA_SPI_IDLE_VAL;
 124
 125                 debug("%s: tx:%x ", __func__, data);
 126                 writel(data, &regs->txdata);
 127
 128                 start = get_timer(0);
 129                 while (1) {
 130                         reg = readl(&regs->status);
 131                         if (reg & ALTERA_SPI_STATUS_RRDY_MSK)
 132                                 break;
 133                         if (get_timer(start) > (CONFIG_SYS_HZ / 1000)) {
 134                                 debug("%s: Transmission timed out!\n", __func__);
 135                                 return -1;
 136                         }
 137                 }
 138
 139                 data = readl(&regs->rxdata);
 140                 if (rxp)
 141                         *rxp++ = data & 0xff;
 142
 143                 debug("rx:%x\n", data);
 144         }
 145
 146 done:
 147         if (flags & SPI_XFER_END)
 148                 spi_cs_deactivate(dev);
 149
 150         return 0;
 151 }
 152
 153 static int altera_spi_set_speed(struct udevice *bus, uint speed)
 154 {
 155         return 0;
 156 }
 157
 158 static int altera_spi_set_mode(struct udevice *bus, uint mode)
 159 {
 160         return 0;
 161 }
 162
 163 static int altera_spi_probe(struct udevice *bus)
 164 {
 165         struct altera_spi_platdata *plat = dev_get_platdata(bus);
 166         struct altera_spi_priv *priv = dev_get_priv(bus);
 167
 168         priv->regs = plat->regs;
 169
 170         return 0;
 171 }
 172
 173 static int altera_spi_ofdata_to_platdata(struct udevice *bus)
 174 {
 175         struct altera_spi_platdata *plat = dev_get_platdata(bus);
 176
 177         plat->regs = ioremap(dev_get_addr(bus),
 178                 sizeof(struct altera_spi_regs));
 179
 180         return 0;
 181 }
 182
 183 static const struct dm_spi_ops altera_spi_ops = {
 184         .claim_bus      = altera_spi_claim_bus,
 185         .release_bus    = altera_spi_release_bus,
 186         .xfer           = altera_spi_xfer,
 187         .set_speed      = altera_spi_set_speed,
 188         .set_mode       = altera_spi_set_mode,
 189         /*
 190          * cs_info is not needed, since we require all chip selects to be
 191          * in the device tree explicitly
 192          */
 193 };
 194
 195 static const struct udevice_id altera_spi_ids[] = {
 196         { .compatible = "altr,spi-1.0", },
 197         { }
 198 };
 199
 200 U_BOOT_DRIVER(altera_spi) = {
 201         .name   = "altera_spi",
 202         .id     = UCLASS_SPI,
 203         .of_match = altera_spi_ids,
 204         .ops    = &altera_spi_ops,
 205         .ofdata_to_platdata = altera_spi_ofdata_to_platdata,
 206         .platdata_auto_alloc_size = sizeof(struct altera_spi_platdata),
 207         .priv_auto_alloc_size = sizeof(struct altera_spi_priv),
 208         .probe  = altera_spi_probe,
 209 };